Sherlock Holmes: Forensic Science Pioneer?

A Scientific Foundation  

Due to his wild success in the literary space, Arthur Conan Doyle’s medical background is oftentimes forgotten. However, long before he put pen to paper, Doyle was a practicing doctor with a prestigious degree from the University of Edinburgh. During his studies, he was mentored by Dr. Joseph Bell, who is often credited as one of the pioneers of forensic science. 

Bell was famous for using keen observation in treating his patients, often examining their hands, clothing, and appearance to get a diagnosis. His skills drew the attention of the Edinburgh police, who consulted him on several crimes. It is even rumoured that Bell was recruited by Scotland Yard to assist in the Jack the Ripper investigation in 1888. Doyle often stated that Bell was his inspiration for Sherlock and wrote to his former mentor in 1892, saying: "It is most certainly to you that I owe Sherlock Holmes… round the centre of deduction and inference and observation which I have heard you inculcate, I have tried to build up a man.”  

Crime Scene Preservation  

In the nineteenth century, little emphasis was put on physical evidence, with investigators relying mainly on witness testimony and suspect interrogation to catch criminals. As a result, crime scenes were often compromised, sometimes by the detectives themselves. For example, police erased a message written in chalk near one of Jack the Ripper’s victims that referenced Judaism for fear it would spark anti-Semitic riots, even though it might have been their only lead. 

Sherlock Holmes repeatedly expresses frustration at how his contemporaries at Scotland Yard treat crime scenes. “Oh, how simple it would all have been had I been here before they came like a herd of buffalo and wallowed all over it,” he laments in The Boscombe Valley Mystery, referencing how officers trampled over crucial footprints. 

It wasn’t until 1893 that a systematic approach to crime scene investigation began to take shape with the publication of Hans Gross’s Handbook for Criminal Investigators. In his seminal work, Gross emphasised the importance of documenting evidence before moving it and cordoning off crime scenes—methods the fictional detective had used for years.  

Fingerprint Analysis  

In The Sign of Four, published in 1890, Sherlock Holmes mentions the use of fingerprint analysis to track down a culprit. To the modern reader, this sounds like standard detective work, but it was revolutionary for the time. 

By this point, fingerprinting’s potential was well-known in criminology, but it wasn’t until 1894, when Sir Francis Galton published his study Fingerprints, that the scientific community began taking it seriously. Holmes’s use of the method significantly predated Scotland Yard, which established its Fingerprint Bureau in 1901. 

Document Analysis  

The roots of handwriting analysis can be traced all the way back to ancient China and Rome. However, it wasn’t until the late nineteenth century that it emerged as a forensic science, and Sherlock Holmes was one of its earliest adopters. In The Adventure of the Reigate Squires, for example, he uses it to identify not one but two suspects. 

However, it was in typewriter analysis that Holmes really shined, with some scholars even crediting him as being among the first to use it to identify a criminal. “It is a curious thing,” the great detective remarks in A Case of Identity, “that a typewriter has really quite as much individuality as a man’s handwriting. Unless they are quite new, no two of them write exactly alike. Some letters get more worn than others, and some wear only on one side…”  

Conan Doyle’s reference to this method predates the earliest professional text on typewriter analysis by three years, and scholars are still unsure how he got it so right.

Trace Evidence  

One of the hallmarks of Holmes’s investigative style is the attention he pays to minute, seemingly insignificant evidence. For example, he is an expert in tobacco ash and uses this skill to help catch criminals in stories like A Study in Scarlet. In The Adventure of the Devil’s Foot, a scant amount of a mysterious brown powder leads to an unlikely killer, and in The Five Orange Pips, a distinctive clay and chalk mixture tells Sherlock where someone has been. 

All of these clues are what is today known as trace evidence. In the early twentieth century, forensic science pioneer Dr. Edmond Locard developed what is known as the “exchange principle.” This theory is based on the idea that “every contact leaves a trace,” in other words, perpetrators will always leave something, no matter how small, at the scene of the crime and take something away with them. Be it tobacco ash or fibres from a carpet, these microscopic traces can be crucial in helping investigators establish connections between suspects, places, and events. 

Locard himself even credited Conan Doyle’s fictional detective as one of his inspirations, stating:

Sherlock Holmes was the first to realise the importance of dust. I merely copied his methods.

Dr. Edmond Locard, Forensic Science Pioneer

Legacy  

While Sherlock Holmes certainly did not invent modern forensics, it is fair to say that he popularised it. Conan Doyle’s stories introduced the public to cutting-edge, science-based crime-solving methods, helping readers to understand them as the justice system rapidly changed. In the process, he also inspired generations of forensic scientists and investigators to pursue the truth, no matter how elusive it might seem